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Muhammad Arif

Publications and source records attributed to Muhammad Arif.

12 recordsLinked to original sources
PubMed2026

Genome-wide characterization of the tomato PERK gene family and its expression profiling under abiotic stresses.

UNLABELLED: This study presents the first systematic genome-wide characterization of the proline-rich extensin-like receptor kinases (PERK) gene family in tomato (Solanum lycopersicum) and their transcriptional responses under abiotic stresses. Using the latest SL4.0/ITAG4.0 genome assembly, we identified six SlPERK genes, all harboring the conserved Ser/Thr protein kinase domain. Evolutionary and structural analyses revealed strong purifying selection (Ka/Ks&#x2009;<&#x2009;1), distinct exon-intron organizations, and the presence of stress- and hormone-responsive cis-regulatory elements in their promoters. Furthermore, post-transcriptional regulation by 57 miRNAs and complex protein-protein interaction networks were predicted. To validate their stress-responsive roles, two tomato cultivars (GMOTL-1 and Roma) were subjected to cold, heat, and salinity treatments. Quantitative RT-PCR analysis revealed cultivar-specific expression dynamics: SlPERK4 exhibited strong transient induction under cold and heat stress, while SlPERK6 was highly responsive to salinity. Notably, the GMOTL-1 cultivar displayed significantly higher and broader stress-responsive expression profiles compared to Roma, indicating a potential role of these SlPERK genes in cultivar-specific stress tolerance. These findings provide a comprehensive genomic resource and establish a critical foundation for the functional validation and molecular breeding for stress-resilience tomato cultivars. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05044-y.

Abiotic stress↗
PubMed2006

Regulation of the bacterial cell cycle by an integrated genetic circuit.

How bacteria regulate cell cycle progression at a molecular level is a fundamental but poorly understood problem. In Caulobacter crescentus, two-component signal transduction proteins are crucial for cell cycle regulation, but the connectivity of regulators involved has remained elusive and key factors are unidentified. Here we identify ChpT, an essential histidine phosphotransferase that controls the activity of CtrA, the master cell cycle regulator. We show that the essential histidine kinase CckA initiates two phosphorelays, each requiring ChpT, which lead to the phosphorylation and stabilization of CtrA. Downregulation of CckA activity therefore results in the dephosphorylation and degradation of CtrA, which in turn allow the initiation of DNA replication. Furthermore, we show that CtrA triggers its own destruction by promoting cell division and inducing synthesis of the essential regulator DivK, which feeds back to downregulate CckA immediately before S phase. Our results define a single integrated circuit whose components and connectivity can account for the cell cycle oscillations of CtrA in Caulobacter.

Bacterial Proteins↗
PubMed2006

Complexity analysis of stride interval time series by threshold dependent symbolic entropy.

The stride interval of human gait fluctuates in complex fashion. It reflects the rhythm of the locomotor system. The temporal fluctuations in the stride interval provide us a non-invasive technique to evaluate the effects of neurological impairments on gait and its changes with age and disease. In this paper, we have used threshold dependent symbolic entropy, which is based on symbolic nonlinear time series analysis to study complexity of gait of control and neurodegenerative disease subjects. Symbolic entropy characterizes quantitatively the complexity even in time series having relatively few data points. We have calculated normalized corrected Shannon entropy (NCSE) of symbolic sequences extracted from stride interval time series. This measure of complexity showed significant difference between control and neurodegenerative disease subjects for a certain range of thresholds. We have also investigated complexity of physiological signal and randomized noisy data. In the study, we have found that the complexity of physiological signal was higher than that of random signals at short threshold values.

Biological Clocks↗
PubMed2006

A phosphorelay system controls stalk biogenesis during cell cycle progression in Caulobacter crescentus.

A fundamental question in developmental biology is how morphogenesis is coordinated with cell cycle progression. In Caulobacter crescentus, each cell cycle produces morphologically distinct daughter cells, a stalked cell and a flagellated swarmer cell. Construction of both the flagellum and stalk requires the alternative sigma factor RpoN (sigma(54)). Here we report that a sigma(54)-dependent activator, TacA, is required for cell cycle regulated stalk biogenesis by collaborating with RpoN to activate gene expression. We have also identified the first histidine phosphotransferase in C. crescentus, ShpA, and show that it too is required for stalk biogenesis. Using a systematic biochemical technique called phosphotransfer profiling we have identified a multicomponent phosphorelay which leads from the hybrid histidine kinase ShkA to ShpA and finally to TacA. This pathway functions in vivo to phosphorylate and hence, activate TacA. Finally, whole genome microarrays were used to identify candidate members of the TacA regulon, and we show that at least one target gene, staR, regulates stalk length. This is the first example of a general method for identifying the connectivity of a phosphorelay and can be applied to any organism with two-component signal transduction systems.

Amino Acid Sequence↗
PubMed2006

Assessment of respiratory muscles endurance in diabetic patients.

OBJECTIVE: Respiratory muscle endurance is of interest in pulmonary, critical care and many other areas of medicine. The maximal voluntary ventilation (MVV) test is an objective dynamic method for measuring the working capacity of respiratory muscles. Therefore, we designed the present study to determine the effect imposed by diabetes mellitus on respiratory muscle endurance in Saudi diabetic patients. METHODS: We conducted this study in the Department of Physiology, College of Medicine, King Khalid University Hospital and Diabetic Centre, King Abdul-Aziz University Hospital, Riyadh, Saudi Arabia during the year 2002-2004. In this study, we recruited 39 male diabetic patients and equal number of control subjects and all participants were non-smokers with age range of 23-71 years. The subjects were matched for age, height and weight. We determined the respiratory muscles endurance by a direct MVV test during inspiratory and expiratory phases of respiration by using a MP-100 student Bio Pac system and compared the results using a paired t-test. RESULTS: In inspiratory and expiratory phases of respiration, diabetic patients showed a significant reduction in the mean values of direct MVV test (p<0.001) relative to their matched controls. CONCLUSION: We conclude that in diabetic patients the respiratory muscles endurance is impaired by a decreased in MVV values. This decline in MVV further showed that the diabetic patients have a reduced inhaled and exhaled volumes during consecutive breaths.

Adult↗
PubMed2006

Lung function in type 2 Saudi diabetic patients.

OBJECTIVE: To study the effects of type 2 diabetes mellitus on lung function and to determine its severity in relation to duration of disease. METHODS: We conducted this study in the Department of Physiology, College of Medicine, King Khalid University Hospital and Diabetic Centre, King Abdul-Aziz University Hospital, Riyadh, Saudi Arabia during the year 2002 - 2004. A group of 32 apparently healthy volunteer male type 2 diabetic patients were randomly selected with an age range from 24-73 years. We matched the diabetic patients with another group of 40 control healthy male subjects in terms of age, height, weight, and socioeconomic status. Both groups met with exclusion criteria as per standard. Spirometry was performed on an Electronic Spirometer (Schiller AT-2 Plus, Switzerland) and results were compared using the 2-tailed student t-test. RESULTS: Diabetic patients showed a significant reduction in the forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) relative to their matched controls. However, there were no significant difference in the forced expiratory ratio (FEV1/FVC%) and middle half of the FVC (FEF 25-75%) between the groups. CONCLUSION: Lung function in type 2 diabetic patients is impaired by a decrease in FVC, FEV1 and PEF, as compared to their matched controls. Stratification of results by years of disease showed a dose-response effect on lung function.

Adult↗
PubMed2005

Squamous cell carcinoma lower lip - an experience with Karapandzic technique.

Carcinoma of the lip is a common cancer of head and neck area. It occurs frequently on the lower lip of middle-aged and elderly males who have a history of chronic sun exposure. Surgical excision and radiotherapy are regarded as equally effective treatment options, but preferred method is surgical excision. Karapandzic technique provides myoneurovascular pedicled advancement flap for reconstruction of the defect after surgical excision. It is a simple and safe technique, functionally and esthetically, sacrifices little tissue, heals rapidly and is effective for repair of defects covering 1/3 to 4/5 of the lower lip. We report a 62 years male who presented with a large, fungating, pus-discharging and tender mass of lower lip. Biopsy confirmed squamous cell carcinoma. Tumor was excised and defect was reconstructed using Karapandzic technique. Patient remained asymptomatic during follow-up visits.

Carcinoma, Squamous Cell↗
PubMed2005

Lung function in type 1 Saudi diabetic patients.

OBJECTIVE: To determine the effects of type 1 diabetes mellitus on lung function and its gravity in relation to the duration of disease. METHODS: We carried out this study in the Department of Physiology, College of Medicine and Diabetic Center, King Abdul-Aziz University Hospital, King Saud University, Riyadh, Saudi Arabia during the period 2003-2004. We randomly selected a group of 27 apparently healthy volunteer Saudi male type 1 diabetic patients with age ranging from 19-70 years. We matched the diabetic patients with another group of 27 control healthy male subjects in terms of age, height, weight and socioeconomic status. Both groups met with exclusion criteria as per standard. We performed spirometry on an Electronic Spirometer (Schiller AT-2 Plus, Switzerland) and compared the results by a student t-test (2-tailed). RESULTS: Type 1 diabetic patients showed a significant reduction in the forced vital capacity and forced expiratory volume in one second (FEV1) relative to their matched controls. However, there was no significant difference in the forced expiratory ratio, forced expiratory flow; forced expiratory flow and peak expiratory flow (PEF) between the groups. CONCLUSION: It is concluded that lung function in type 1 diabetic patients is impaired by a decrease in FVC and FEV1 as compared to their matched controls. Additionally, the years of disease showed a dose-response effect on lung function.

Adult↗
PubMed2005

Neurochemical estimations of some new quaternary phenacyl-bromopiperidinium compounds.

Considering the fact that N-alkyl substituted quaternary ammonium salts of piperidinium bromide induce brain catecholamine and indoleamine metabolism (Black et al., 1986), we thought it may be valuable to investigate the effects of three selected phenacyl derivatives (I, V and VIII) of piperidine on brain monoamines metabolism in mice (100mg/kg body weight) assuming that these derivatives might alter the brain indoleamine and catecholamine levels differently. Studies are carried out by using HPLC technique. It was found that compound VIII possessed greater neuroleptic activity as compared to compounds I and V.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Spot size and quality of scanning laser correction of higher-order wavefront aberrations.

PURPOSE: To investigate the effect of laser spot size on the outcome of aberration correction with scanning laser corneal ablation. SETTING: Cleveland Clinic Foundation, Cleveland, Ohio, USA. METHODS: Corrections of wavefront aberrations of Zernike modes from the second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0 mm full-width-half-maximum diameters were modeled. The fractional correction and secondary aberration (distortion) were evaluated. RESULTS: Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, a 2.0 mm or smaller beam was adequate for spherocylindrical correction (Zernike second order), a 1.0 mm or smaller beam was adequate for correction of up to fourth-order Zernike modes, and a 0.6 mm or smaller beam was adequate for correction of up to sixth-order Zernike modes. CONCLUSIONS: Since ocular aberrations above the Zernike fourth order are relatively insignificant in normal eyes, current scanning lasers with a beam diameter of 1.0 mm or less are theoretically capable of eliminating most higher-order aberrations.

Computer Simulation↗
PubMedDate not supplied

Homicidal deaths by firearms in Peshawar: an autopsy study.

BACKGROUND: Medico legal autopsies can be valuable sources of information about the distribution of causes of reported deaths, particularly in homicidal cases. The present study provides information regarding the homicidal deaths due to firearm injuries in the district of Peshawar, NWFP, Pakistan. METHODOLOGY: This descriptive study was conducted over the period of the year 2004. Data were collected from the autopsy records of the Department of Forensic Medicine, Khyber Medical College Peshawar and included all reported unnatural deaths from urban and rural areas of district Peshawar on whom autopsies were conducted in the department. RESULTS: Homicidal deaths constituted 77.7% (492/633) of all autopsies for the year 2004. Of 492 homicidal deaths, a vast majority of 452 (91.87%) were caused by firearm injuries. Among these, the male to female ratio was 5.5:1. The most common firearm weapon (418/452, 92.5%) were high velocity rifled weapons (Kalashnikov, rifles, pistols), followed by low velocity rifled weapons (18/452, 3.98%) and shotguns (16/452, 3.54%). A total of 956 injuries were found in various body areas, giving an average of over two injuries per person. The head, face and neck sustained the highest injuries (257, 26.9%), followed by the chest (248, 25.9%) and abdomen (149, 15.6%); the extremities, buttocks and genitalia together sustained 302 (31.6%) injuries. CONCLUSION: The vast majority of reported homicides in Peshawar are caused by firearm injuries, which bring up issues related to possession of firearms and changes in cultural attitudes towards use of firearms, if a decrease in firearm-related homicides is desired.

Adolescent↗